I hope you get your ultrasound done right away. Other than the ache you mentioned, did you experience any stabbing pain in the testicle. It's possible, like others have mentioned that this can be a benign problem but, if it's the result of testicular torsion, something that should be addressed as soon as possible. How are you feeling otherwise? Mood, libido, energy?
TC1: 1996, right orchiectomy, seminoma stage I 3.5 cm mass, radiation therapy (peri-aortic & pelvic 27.3 Gy)
TC2: 2008, left orchiectomy, seminoma stage IA 5 cm mass, left & right prostheses, AndroGel TRT, surveillance at MSKCC